Suspension line for parachutes and the like



\ May12,\'1942' NL. P. FRIEDER "2,282,717

SUSPENSION LINE FOR PARACHUTES AND THE LIKE Filed Oct. 24, 1958 INVENTORLEO/WWO P. FR/EOER QQM M ATTORNEY Patented May 12, 1942 UNITED 's ATEs'PATENT OFFICE Leonard P. Frieder, New York, N. Y.

Application October 24, 1938, Serial No. 236,809

6 Claims.

This invention relates generally to parachutes and has particularreference to the manufacture of suspension cords or shroud lines for usein suspending the load from the sail.

One object of the' invention is to provide a cord of the kind indicated,which is very strong as compared with prior cords of the same crosssection and which is at the same time so constructed that it will yieldto absorb shock when the parachute opens. The construction is such thatthe cord may be used to suspend the load from the outer ends of theseamsconnectingtogether the gores of a parachute sail or it may be extendedalong such seams and be so adjusted as to yieldingly reinforce theseams.

- never exceeding the elastic limits of'the fibers. Y

More specifically the invention includes a novel way or method of makingparachute suspension cords or shroud lines as well as the articleresulting from the method.

With the foregoing and other objects in view the invention consists in anovel construction The fibers or filaments of naturalsilk have sometwist or crimp which adds to the resiliency .oi the completed cord, butone should be taken to get substantially the same tension in all ofthem. When more exact uniformity of tension is advisable the silk fibersmay be stretched under water and then dried, the stretch varyingaccording to the amount of twist or crimp but This stretching and dryingmay be performed before the-fibers are given the slight twist to formthe strands 10, but it has been found to be more convenient and just assatisfactory to do the stretching and drying after the slight twist hasbeen given to the strand.

This stretching and drying brings all the fibers under substantiallyequal tension and the strands have no rough surfaces or loops of singlefibers projecting from the strands.

gether in parallel relation to form what is usually referred to hereinas a tape l2. Eight of these groups or tapes are employed in weaving orbraiding the finished article illustrated. This braiding may be done ona braiding. machine which is The accompanying drawing shows, on a scalewhich is not necessarily the exact one, how the difierentcomponents ofthe cord are first constructed and then assembled into the finishedarticle.

The illustrative embodiment in the drawing is constructed tohold thestrands in the fiator tape relation while performing the braidingoperation, but is otherwise a more or less standard machine. Thebraiding is an over and-under braiding in which the tapes extend inoppositely running spirals as shown, and care is taken to see that thetension is so adjusted that the finished article is a soft loose braidalthough, ofcourse, this may be varied according to specialrequirements. The

finished article has no core of material running lengthwise through itscenter so the finished article may be visualized as operating somewhatin the nature of a spring which will yield and recover when loadisapplied and removed.

Owing to the fact that the strands I 0 are untwisted or substantiallyso, the exposed fibers of the strands will lie substantially parallel onexterior of the finished cord and at angles apsufficient only for thepurpose indicated and performs no function in the load sustainingopera-' the twist a functional purposein theload sustaining operation ofthe cord.

preaching nearer parallelism with the axis of the cord than if thestrands had a relatively high twist. As a result, the fibers orfilaments on the exterior will cause the finished cordor rope to have -avery smooth surface whichwill not catch and fray when dragged over roughsurfaces, or

burn under friction, or pick up dirt. It will be much stronger forthesame cross-section than In the embodiment shown in the drawing eightof the strands above described are brought tohave a part of a shroudline in or along the seam connecting the goresof a parachute, therebycoordinating the extensibility of the cord with the extensibility of theseam, while, at the same time, providing a very strong reinforcementwhen the limit of that extensibility is reached.

One advantage of the construction is that on account of its greatstrength and other characteristics stated it is possible to use a largernumber of suspension cords'or shroud lines for a sail without greatlyincreasing the bulk of the parachute as a whole. This, in turn, makes itpossible to use relatively long and narrow gores. and more of them thanhas heretofore been possible in making a sail, thereby not only.increasing the reinforcement afforded by the more numerous seamsconnecting the gores, but also effecting a betterdistributionof the loadover the sail area. Also, owing to the construction, the lines arecapable of being folded into any sort of a pack or container withoutdanger of weakening at places where sharp folds or bends might occurand, on account of the smooth exterior surface,

there will be noharmfulfriction between the cords or between the cordsand the sail of the parachute when the parachute is put into use.

While silk is preferred and has so far been the only material referredto, rayon filaments may be used instead of silk'and in substantially thesame way. Also, instead ofeither silk or into parallel relation to formeach tape,- and rayon, cotton may be employed, although it hasdisadvantages as compared with either silk or. rayon. When cottonis-used, each of the strands i0 is made up of a plurality of finethreads, each twisted sufficiently to give the maximum strength, broughtinto, parallelism to form the strand, and the strand then given the samesort of low twistasis above described in connection with the silkconstruction. In other words, fine highly twisted cotton threadsare'substituted for the silk or rayon filaments, but'the procedure isotherwise substantially the same in making the article. Owin to the hightwist given to the cotton, filaments or threads, the exterior of thefinished cotton cord or rope will have a smooth exterior like that ofthe silk article.

While the novel cord or ropehas been described in detail, and also themethod of making it, it will be apparent to those skilled in the artthat changes may. be made in the article and ments in parallel relation.

ing endwise to loosen the braid slightly and the cord then flattenedslightly when it is desired to method or producing it which will yieldsubstan tially the same results, all or which changes,

come within the scope or the claims which 101- IOW. v I I What isclaimed is:

1; A method 01 making shroud lines 10mm} 1 chutes and the like whichcomprises the srouD-- ing together of parallel'silk filaments to iorm aplurality of strands, stretching the strands under water and dryingthem, dividing the plu-v rality of strands into groups and bringing the,

of strands into parallel relation to form a plurality of tapes, andbraiding the tapes together to construct a substantially round line. 3.A method of making suspension cords for parachutes and the like whichcomprises constructing strands from substantially untwisted parallelsilk filaments, forming a plurality of flat twistless tapes by bringinga plurality of strands then'braiding said tapes together while flat tocomplete the cord. 4. A suspension cord for parachutes and the likeconsisting of a plurality of groups of strands braided together, each oisaid strands consisting of a plurality of permanently stretched silkfila- 5. A suspension cord for parachutes and the like consisting of aplurality oi'fiat tapes loosely braided together while fiatfeach of saidtapes being composed of a plurality of parallel strands,

.and ea'ch of the strands being composed of a plurality of parallelpermanently stretched silk filaments with the filaments in each strandin substantially untwisted condition.

6; A method of making suspension cords for parachutes and the like whichcomprises constructing substantially untwisted strandsfrom parallelfilaments-constructing a plurality of

